The densification rate of the Mg n TiC powder

The densification rate of the Mg/n-TiC powder was lower than that of the microcrystalline powder due to the work-hardening effect. The addition of n-TiC reinforcement decreased the densification (K-value) rate, and the plastic deformation capacity of composite powders was significantly reduced by the MA. The powder density always depends on the size, morphology and size distribution of the particles [35,37].
Table 1 shows the densities of Mg for various n-TiC contents (wt%) at 350°C, 400°C, and 450°C. The density initiates to be positively linked to the sintering temperature from 350°C to 450°C. The sinterability of the compacted materials was evaluated by using the following equation [39]:where , and are the sintered, green and theoretical densities, respectively. Fig. 8 shows the sinterability of the compacted materials as a function of the wt% of n-TiC reinforcement.
The sinterability of nanocomposites decreased for a increasing content of the n-TiC nanoparticles from 5 to 15wt%, due to the morphology of the milled powder. The sinterability was found to be positively correlated with the sintering temperatures (350–450°C). The decrease in the sinterability was very high at 450°C compared to the sinterability at both 350°C and 400°C. The compaction characteristic curves for the Mg/n-TiC nanocomposite powders are presented in Fig. 8. In general, the curves indicate the typical powder compressibility behaviour of metallic powders, i.e. the density increases with increasing compaction pressure at a decelerating rate. It is important to note that the densification behaviour was influenced by the powder characteristics and the method of processing.
In general, the density was positively correlated with the compaction pressure at decelerating rates during cold uni-axial pressing or compaction. The compaction behaviour of Mg/n-TiC powders was also observed for comparison purposes. In this study, the Mg/n-TiC exhibited excellent densification behaviour for the various ranges of compaction pressures (see Fig. 9).

Compressive strength examination
In order to find out the hoechst 33342 cost strength of the Mg/n-TiC composite, the experiment was carried out using flat faced dies and a hydraulic operated universal compression testing machine of having 1MN capacity. The testing was carried out on room temperature. The compressive strength of metal matrix composite depends not only on the mechanical properties of the metal matrix and the ceramic particles but also on the volume fraction, structure and distribution of the ceramic particles. The interfacial bonding between the metal matrix and the ceramic particles and the amount of defects in the composite also affect the compressive strength. Table 3 shows the ultimate compression stress of the composites before sintering and after sintering.

Conclusion

Introduction
Study associated with natural convection flow of an electrically conducting fluid in the presence of an external magnetic field has received considerable interest due to the enormous applications in various branches of industry, science and technology such as, fire engineering, combustion modelling, geophysics, the cooling of nuclear reactors, operation of magnetohydrodynamic (MHD) generators, and plasma studies. Application of a magnetic field has been found to be effective in controlling the melt convection during crystal growth from melts under terrestrial conditions and has now been widely practises in the metals and semiconductor industries. Several studies have been reported on MHD convective flow under different physical situations. Record of such investigations can be found in the works of Cramer and Pai [1], Chawla [2], Das et al. [3], Sheikholesslami and Gorgi-Bandpy [4], Sheikholesslami et al. [5,6], Chauhan and Rastogi [7], Ibrahim and Makinde [8], Farhad et al. [9,10].
Although there are many studies on natural convection flow of an electrically conducting fluid in channels, there are only a few studies regarding natural convection flow of an electrically conducting fluid in microchannel and annular microchannel. In recent years, the present authors and their collaborators have carried out a number of studies on MHD natural convection covering several aspects. For instance, Jha et al. [11] analytically studied the fully developed steady natural convection flow of conducting fluid in a vertical parallel plate microchannel in the presence of transverse magnetic field. The effect of Hartmann number was reported to decrease the volume flow rate. The combined influence of externally applied transverse magnetic field and suction/injection on steady natural convection flow of conducting fluid in a vertical microchannel was carried out by Jha et al. [12]. In another work, Jha et al. [13] examined the effect of wall surface curvature on transient MHD free convective flow in vertical micro-concentric-annuli. Jha et al. [14] studied exact solution of steady fully developed natural convection flow of viscous, incompressible, and electrically conducting fluid in a vertical annular microchannel. Recently, Jha and Aina [15] presented the MHD natural convection flow in a vertical micro-porous-annulus (MPA) in the presence of radial magnetic field. Also, the MHD natural convection flow in vertical micro-concentric-annuli (MCA) in the presence of radial magnetic field has been analysed by Jha et al. [16].